The long term goals of this proposal are to study the basic mechanisms of gene regulation in hepatoma cells at the molecular level, and to better understand the characteristics and possible function of hepatoma-associated nonhistone proteins. We have produced antibodies to hepatoma nonhistone proteins which are present in active chromatin of hepatoma. In this application we propose to isolate and characterize these nonhistone proteins. Antibodies to hepatoma-associated nonhistone proteins will be linked to agarose and used to isolate immunogenic hepatoma nonhistone proteins associated with active chromatin. Purified nonhistone proteins will be characterized by analytical electrofocusing, tryptic peptide mapping, amino acid analysis and sequencing. Chemical modification of these nonhistone proteins will also be studied. In addition to these, proteins will be used to raise monospecific antibodies in rabbits or to produce monoclonal antibodies in hybridoma cells. Monospecific antibodies will be used to isolate specific mRNA for cloning or will be used as probes to screen specific cDNA clones from a rat hepatoma cDNA library in Lambda gt 11. Cloned cDNAs complimentary to hepatoma-associated nonhistone protein mRNAs will be used as probes to study the differential expression of the corresponding genes in normal rat liver, hepatoma and other tissus.